Cancer is an area where technological breakthroughs have resulted in major advances in our understanding of the molecular basis of disease. Knowledge concerning the role of key signaling proteins in cancer has prompted attempts to develop anti-cancer agents that are directed against signaling targets such as the epidermal growth factor receptor (EGFR). Considerable research has centered on antagonizing the tyrosine kinase activity of the EGFR, and EGFR mutations have recently been identified that correlate with tumor shrinkage following treatment with kinase inhibitors. However, clinical trials in non-small cell lung cancer (NSCLC) have revealed highly variable levels of effectiveness in cancer patients to kinase antagonists such as gefitinib or erlotinib. Moreover, little is known regarding the precise mechanisms of action of these anti-cancer agents in human tumors, primarily due to the difficulty in performing relevant molecular assays on limited tissue material. Uncertainty about how these agents affect EGFR status/signaling in human tumors has made clinical development of these drugs extremely difficult. Accordingly, the present project seeks to further develop a technology based on a new class of exquisitely sensitive tools that use nanostructured surfaces and liquid crystals (LCs) to amplify and image molecular interactions. Our preliminary data show that we can: a) fabricate surfaces with nanometer-scale topographies, b) identify EGFR expression and phosphorylation status in cell preparations using LCs, and c) detect inhibition of EGFR phosphorylation status and kinase activity in cell extracts following exposure to EGFR antagonists. Our goals are to refine, validate, and implement this methodology to allow high throughput screening on limited clinical specimens, and to ultimately use this technology to assess which tumors are most likely to respond to EGFR antagonists. The proposed Aims are: 1) Optimize the torque balance method for utilizing LC-based assays to report EGFR expression and phosphorylation status in cell preparations in a highly sensitive, reproducible and quantitative manner;2) Using LC technology, evaluate and refine the concept that small numbers of cells are sufficient to report the expression, phosphorylation status and tyrosine kinase activity of the EGFR in a sensitive and quantitative fashion. It is anticipated that this research will provide a powerful and novel tool for the study, diagnosis, and treatment of cancer.